Apparatus for the treatment of sheet materials



Jan. 31, 1967 APPARATUS FOR THE TREATMENT OF SHEET MATERIALS Fil ed Oct. 15, 1963 H.. H. GREE-N ETAL 2 sheets-s eet 2 p 2 x d 1 0 T L //////1 United States Patent 3,300,874 APPARATUS FOR THE TREATMENT OF SHEET MATERIALS Harold Hurdley Green, Castle Bromwich, and Alec Dennis Robinson, Birmingham, England, assignors to Dunlop Rubber Company Limited, London, England, a company of Great Britain Filed Oct. 15, 1963, Ser. No. 316,313 Claims priority, application Great Britain, Oct. 24, 1962, 40,217/ 62 1 Claim. (Cl. 34-242) This invention relates to apparatus for the treatment of sheet materials such as continuous sheets of textile fabric.

In the specification of UK. Patent No. 885,513 apparatus is described for treating lengths of textile fabric by passing the fabric through a heated bed consisting of particulate material such as particles of sand or minute glass beads known as ballotini, the bed being maintained in a fluidised or suspended state by a current of gas passing through the bed.

It is an object of the present invention to provide improved closure means for the base of a fiuidisable bed container which will permit the entry of a continuous sheet of textile fabric and a supply of compressed gas into the container and will minimise or eliminate the loss of particulate material therefrom.

According to the present invention a closure for a fiuidisable bed container for treating lengths of sheet material comprises a pressure chamber having an inlet for compressed gas and an inlet and outlet slots each provided with a pair of flexible and resilient sealing strips for sealing engagement with a length of sheet material during its passage through the slots.

Preferably, in each pair of strips, the strips are parallel to one another longitudinally of the strips'and are relatively inclined in a transverse cross-section of the strips, and adjacent longitudinal edges of the strips lie mutually in contact and distort one another to form the strips in said cross-section into a substantially V- or Y-shaped seal.

Preferably also, the sealing strips are formed from polytetrafluorethylene, a substance having a low coefficient of friction, but they may be formed from flexible, resilient metal or rubber and the strips may be formed into fine combs of these materials.

it is also preferable that the sealing strips are detachably mounted on the pressure chamber to allow for ease of replacement in the event of the strips becoming worn during use.

One embodiment of the invention will now be described, by way of example, for use in the heat treatment of nylon cord sheet material prior to its use in the manufacture of reinforcements for pneumatic tires, the description referring to the accompanying drawings in which:

FIGURE 1 is a transverse and vertical cross-sectional view of a closure assembled on to, and forming the base of, a fiuidisable bed container;

FIGURE 2 is a view similar to FIGURE 1, of a modification of the closure shown in FIGURE 1.

A closure 1 for a fiuidisable bed container 2, as shown in FIGURE 1, comprises an open-topped box 3 of rectangular cross-section. The base 4 of the box is provided with a slot 5 formed along the longitudinal centerline thereof and extending for substantially the whole length of the box, the base of the box forming the top of a pressure chamber 6 air-tightly ecured beneath the container by means of a plurality of bolts 6:: and a sealing gasket 6b. The box is also provided with two plates 7 extending longitudinally thereof, each plate spanning a ICC portion of the box between a top of a longitudinal wall 8 and an adjacent side of the slot 5. The plates form a nozzle, the inner surfaces of the nozzle diverging from an inlet end thereof leading from the slot, to an outlet end remote from the slot at the top of the box.

The pressure chamber 6 is of rectangular cross-section as shown in FIGURE 1 and spans the slot 5 formed in the base of the box, the slot 5 being an outlet slot for sheet material issuing from the pressure chamber. The pressure chamber is provided in one of its walls 9 and near its base 10 with an inlet 11 for compressed air. The base 10 of the chamber is formed with a sheet material inlet slot 12, the slot 12 being located along the centerline of the base and in vertical alignment with the outlet slot 5. Y

The side 13 of the pressure chamber is removably attached to the chamber 6, to permit access to the interior of the chamber, by means of bolts 6a and a plurality of nuts, bolts and washers 6c, the side 13 being air-tightly sealed to the base by means of a gasket 6d.

Each of the slots 5 and 12 is provided with a pair of sealing strips 14 of polytetrafluorethylene co-extensive with the length of the slot. In a longitudinal direction of the strip, the strips of each pair are parallel to one another. Each strip of each pair is detachably held by a clamping plate 15 and bolts 15a disposed on the side of the slot to be approached first by incoming sheet fabric material 19, the strips of each pair, as shown in FIGURE 1, being relatively inclined in transverse cross-section at a mutual angle of the strips making equal angles with respect to a predetermined line of approach of sheet material 19. In the case of the strips associated with the inlet slot 12 the strips are inclined together and directed into the pressure chamber, and in the case of the strips as sociated with the outlet slot 5, these strips are inclined together and directed outwardly of the pressure chamber, The clamps are fluid-tightly sealed to the sides of theslots by seals 15b. 7

Each strip 14 is of width greater than the width necessary merely to contact the adjacent edge of the other strip of the pair so that adjacent edge portions of the strips of each pair distort one another to form a substantially inverted Y-shape in cross-section, considerable pressure being exerted therebetween.

When the closure is to be used, it is attached to the open base of the fiuidisable container 2, by brackets 16 and bolts 17 securing the closure to a supporting framework 18, so that the two plates 7 in the open-topped box forming the divergent nozzle and leading from the slot 5, open into the container. The side 13 of the pressure chamber is removed and the free end of a sheet 19 of fabric material is passed vertically upwards from around a freely rotatable roller 20 horizontally disposedbeneath the chamber, between the adjacent sealing strips 14 of the base 10 and through the slot 12, the sheet continuing in a straight path vertically upwards between the sealing strips 14 disposed on the underside of the base of the open-topped box and through the outlet slot 5, up between the divergent nozzle plates 7, and through the container 2 which is filled with a fluidisablle bed of ballotini, to a suitable take-off device. The side 13 of the pressure chamber is then replaced.

When the device is actually in operation, compressed air is supplied to the pressure chamber through the inlet 11 at a pressure suflicient to maintain a gauge pressure therein of, for example, four pounds per square inch in excess of the ambient atmospheric pressure. Sheet fabric material passes continuously through the device, the strips 14 associated with the slot 12 bearing against the sides of the sheet and, at the edges of the sheet, bearing upon one another and so sealing the air within the chamber. This sealing is also assisted by the pressure within the chamber which'urges the strips into engagement with the sheet 19. However, the pressure in the chamber is suflicient to hold the strips 14- associated with the slot 5 slightly apart thus permitting the sheet to pass therebetween with the minimum of drag and permitting the air to leave the chamber and fluidise the bed of ballotini. The .air pressure is also sufliciently large to ensure that little or no ballotini fall into the pressure chamber. In practice, it is found, with advantage, that the required minimum gauge pressure of compressed air within the pressure chamber is determined by the flow of air needed to fluidise the bed sufliciently rather than the pressure needed to prevent ballotini from falling through the slot into the pressure chamber.

The purpose of the divergent nozzle is to spread the flow of air gradually over the whole horizontal crosssection of the fluidisable bed thus reducing or eliminating any tendency of localised high and low pressure areas developing in the fluidisable bed container. In practice, of course, the compressed air may be heated or cooled before entering the pressure chamber according to the treatment to be given to the sheet of fabric material.

In the event of an interruption in the supply of compressed air, the sealing strips associated with the slot 5 are sufficiently resilient to close onto the sheet and prevent a flood of ballotini into the pressure chamber. The strips are also sufliciently flexible to allow a joint of approximately ,5 inch thickness between adiacent sheets to pass through the seals without producing undue strain in the material.

A modification of the preferred embodiment of the invention is shown in FIGURE 2, in which parts similar in construction to those already described are given identical reference numerals. Instead of the inlet slot being located in the base of the pressure chamber, as in the construction of FIGURE 1, a pressure chamber 21 is provided with an inlet slot 22 in one of its vertical walls 23, the slot extending horizontally of the 'wall in a position adjacent the base of the pressure chamber. Two strips of polytetrafluorethylene 24 are coextensive with the slot and are detachably held in place by clamps 25 and bolts 25a, the strips being relatively inclined in the manner described above for the strips 14. The clamps are fluid-tightly sealed to the chamber by seals 2517. A freely rotatable roller 26 is mounted in suitable bearings (not shown) within and along the length of the pressure chamber in such a position that a length of sheet fabric material may be passed partly downwardly at an approximate angle of 45 to the horizontal through the inlet slot 22, beneath the roller 13 and vertically upwardly through the outlet slot 5. The base 27 of the pressure chamber is detachable for access to the interior thereof, the base being secured to the chamber by bolts 27a, a sealing gasket 27b being provided to fluid-tightly seal the base to the chamber.

In use, it is necessary to remove the base 27 of the chamber to allow the material to be fed through the strips 24 and inlet slot 22 around the roller 26, vertically upwards between the sealing strips 14 and outlet slot 5, between the divergent plates 7, and into the container 2. The operation of the device is similar to that described above.

In the embodiment described with reference to FIG- URE 1, no rotatable parts are required in the closure for feeding sheet material through the closure and into the fluidisable bed container. In both the embodiment and the modification thereof, the sealing strips when worn are relatively cheap to replace compared with wearing parts in other fluidisable bed apparatus, and because of their detachable nature and the provision of removable access panels in the pressure chamber, the seals are also quickly and easily replaceable.

Furthermore, as the loss of ballotini is reduced or eliminated, a more constant temperature may be maintained within the fiuidizable bed than is possible with other apparatus in which the loss of particulate material is greater. The constancy of bed temperature results in a more uniform quality of material being produced.

Having now described our invention, what we claim is:

A fluidized bed comprising a container having an upper compartment for said fluidized bed and a pressure chamber below and secured air-tightly to said compartment, said compartment having an exit slot from said pressure chamber upwardly to said compartment and said pressure chamber having :an inlet slot for delivery of fabric into said pressure chamber in position to pass upwardly through said exit slot, sealing means for said exit slot comprising a pair of strips of resilient, flexible composition secured to said compartment to enclose said exit slot and extending at angles toward the interior of said compartment to meet tangentially to form a seal and to diverge for the passage of fabric and of air passing under pressure through said exit slot, a pair of strips of resilient flexible composition secured to said pressure chamber to enclose said inlet slot and extending toward the interior of said pressure chamber at complementary angles to :a tangential vcontact and displaceable to permit passage of a fabric between them and pressed by the fluid pressure in said pressure chamber into fluid-tight contact with each other and with said fabric and a pair of imperforate walls diverging upwardly from said exit slot to provide an upwardly increasing area for the passage of fluid from said exit slot into said fluidising compartment.

References Cited by the Examiner UNITED STATES PATENTS 2,220,522 11/1940 Ives 34242X 2,289,753 7/1942 ca stan 34-242 X 2,598,000 5/1952 Knopp et al. 34-242 X 2,724,908 11/1955 Shaw 34-242 X 2,971,242 2/1961 Doleman et a1. 34-242 X 2,974,512 3/1931 Carter 34 242 X OTHER REFERENCES F. W. Billmeyer, Jr., Textbook of Polymer Chemistry, Interscience Publishers, Inc., N.Y., 1957, p. 323.

' FREDERICK L. MATTESON, 111., Primary Examiner. 

